3i^3(i - 2) - 3i =

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Understand the Problem

The question requires evaluating the expression involving imaginary numbers, specifically simplifying the expression 3i^3(i - 2) - 3i.

Answer

The simplified expression is \( 3 + 3i \).
Answer for screen readers

The simplified expression is ( 3 + 3i ).

Steps to Solve

  1. Calculate $i^3$

Recall that ( i^2 = -1 ). Therefore, ( i^3 = i^2 \cdot i = -1 \cdot i = -i ).

  1. Substitute $i^3$ into the expression

Replace ( i^3 ) in the original expression: $$ 3i^3(i - 2) - 3i = 3(-i)(i - 2) - 3i $$

  1. Distribute $3(-i)$

Now, distribute ( 3(-i) ) into ( (i - 2) ): $$ 3(-i)(i) - 3(-i)(2) - 3i = -3i^2 + 6i - 3i $$

  1. Simplify $-3i^2$

Since ( i^2 = -1 ): $$ -3i^2 = -3(-1) = 3 $$

  1. Combine like terms

Add the terms together: $$ 3 + 6i - 3i = 3 + 3i $$

The simplified expression is ( 3 + 3i ).

More Information

The expression ( 3 + 3i ) indicates that there is a real part (3) and an imaginary part (3i). Imaginary numbers are often used in complex number calculations and have applications in engineering and physics.

Tips

  • Confusing ( i^3 ) with ( i^2 ): Remember that ( i^3 = -i ), not ( i ).
  • Forgetting to distribute properly when multiplying terms.

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